Stabilization of halogenated polyolefin compositions



United States Patent 3,355,423 STABILIZATION 0F HALOGENATED POLYOLEFZN COMPOSITIONS James P. Scullin, Pompton Lakes, and Arthur F. Fletcher, Elizabeth, N.J., assignors, by mesne assignments, to Tenneco Chemicals, Inc., a corporation of Delaware No Drawing. Filed Sept. 25, 1962, Ser. No. 226,152 3 Claims. (Cl. 260-4535) This invention relates to the stabilization of halogenated polyolefins. More particularly it relates to halogenated polyolefin compositions that are stabilized against degradation under conditions of elevated temperatures and/or mechanical working.

Halogenated polyolefins undergo appreciable darkening when heated during thermal fabrication operations and when the fabricated articles are exposed to elevated temperatures for prolonged periods. This thermal sensitivity has seriously limited the applications in which the halogenated polyolefin may be employed.

Stabilizers that have been used to impart thermal stability to polyvinyl halide resins have been suggested for use in the stabilization of halogenated polyolefins against decomposition and degradation resulting from exposure to heat and light. These materials, however, have been found in most cases to be unsatisfactory for use as stabilizers for halogenated polyolefin compositions because they impart color to the compositions or because they fail to provide the required heat stability.

It is an object of this invention to provide stabilized halogenated polyolefin compositions. More particularly it is an object to stabilize halogenated polyolefins against the deteriorating eflects of high temperatures. It is a further object to provide halogenated polyolefin compositions which are satisfactorily stabilized and which may be molded, extruded, or otherwise fabricated to form flexible, thermally stable products. Other objects of the invention will be apparent from the description that follows.

The above objects are accomplished in accordance with the present invention by incorporating in a halogenated polyolefin composition a heat stabilizing amount of a stabilizer which comprises a polyhydric alcohol and a phenol. In most cases approximately 1% to and preferably 2% to 6% of the stabilizer based on the weight of the halogenated polyolefin will impart heat stability to the resinous composition. The stabilizer of the present invention is compatible with halogenated polyolefins and generally with the compounding ingredients used with these polymers, and it serves to protect the compositions from thermal degradation both during and subsequent to their fabrication.

The polymers to which this invention applies are the halogenated homopolymers and copolymers of olefins having from 2 to 6 carbon atoms per molecule, such as ethylene, propylene, l-butene, l-pentent, and l-hexene. While these polymers are ordinarily and preferably chlorinated, they may also be brominated, iodinated, or fluorinated. The halogenated polyolefins treated according to this invention generally contain between 5% and 80% by weight of halogen. The novel stabilizers are particularly useful in chlorinated polyethylene compositions derived from normally solid polyethylene and having a chlorine content between approximately 20% and 70%. Processes for the production of these halogenated polyolefins are disclosed in Fawcett, US. Patent No. 2,183,556 and Hogan and Banks, U.S. Patent No. 2,825,721.

The polyhydric alcohols that may be used in the practice of this invention are those that contain at least two hydroxyl groups. These include, for example, ethylene glycol, propylene glycol, neopentyl glycol, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, butanetriol-1,2,3, pentaerythritol, dipentaerythritol, tri- 3,355,423 Patented Nov. 28, 1967 pentaerythritol, erythritol, a-methyl-D-glucoside, sorbitol, and mannitol as well as polymeric polyhydric alcohols, such as hydroxyethylcellulose. Also useful is the polymeric alcohol that has the formula This material, which contains an average of 5.2 hydroxyl groups per mole and which has a molecular weight of op proximately 1150, is marketed as Resinous Polyol X-450 by Shell Chemical Co. The preferred polyhydric alcohols for use in the novel stabilizers are pentaerythritol, clipentaerythritol, t-ripentaerythritol, and sorbitol. A single polyhydric alcohol or a mixture of two or more of these alcohols may be used. When a solid polyhydric alcohol, such as pentaerythritol, is used, it is preferably added to the halogenated polyolefin composition as a finely-divided powder.

The phenols that may be used in the stabilizer mixtures include a wide variety of monohydric and polyhydric phenols. The monohydric phenols include phenol and substituted phenolic compounds in which the substituents are halogen atoms, lower alkyl groups, aryl groups, nitro groups, carbalkoxy groups, and the like. A preferred group.

of monohydric phenols are alkylphenols having the formula (IDH wherein R represents an alkyl group having from 1 to 8 carbon atoms and n represents a number in the range of l to 3. Illustrative of the monohydric phenols that may be present in the stabilizer mixture are the following: cresols, xylenols, carvacrol, thymol, tert. butylphe nols, octylphenols, chlorophenols, bromophenols, nitrophenols, p-hydroxybenzoic acid, salicyclic acid, chlorosalicylic acids, salicylaldehyde, lower alkyl esters of phydroxybenzoic acid, lower alkyl esters of salicylic acid, and alkylphenylphenols.

The polyhydric phenols that may be used include both polynuclear phenols and those phenols that have two or more hydroxyl groups attached to a single aromatic nucleus. A preferred group of polyhydric phenols are polynuclear phenols that have the formula HO Iii. OH ('3 RI wherein each R represents a hydrogen atom or a lower alkyl group, R represents a lower alkyl group or a halogen atom, and n represents a number in the range of 0 to 3. Illustrative of the useful polyhydric phenols are the following: resorcinol, alkylresorcinols, catechol, hydroquinone, sorcinol, hydroxyhydroquinone, hexahydroxybenzene, 2,2bis(4-hydroxyphenyl)propane, 2,2'-bis(4- hydroxydichlorophenyl)propane, 2,2'-bis (4-hydroxyphenyl)butane, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxyphenyl, 1,5-dihydroxynaphthalene, 2,2-methylene bis(4 methyl-6-tert. butylphenol), 4,4'-methylene bis(2,6-ditert. butylphenol), 2,2-butylidene bis(4,6-dimethylphenol), 4,4-butylidene bis(3-methyl-6-tert. butylphenol),

- thol), methylene bis(salicylic acid) 2,2-isopropylidene bis (4-methyl-6-tert. butylphenol), N-salicoyl-p-aminophenol,

4 ent in the amount of approximately 5 to 100 parts by Weight per 100 parts by weight of the polymer. Other heat and light stabilizers as well as pigments, fillers, extenders, solvents, and the like may also be present in the and the like. A single phenol or a mixture of phenols may 5 stabilized resinous compositions. be used in the halogenated polyolefin compositions. If (ic The present invention is further illustrated by the exsired, a thiophenol, such as p-chlorothiophenol, may be amples that follow. It is to be understood, however, that used in place of part or all of the phenol in the stabilizer these examples are given solely for the purpose of illusmixture. tration and that the invention is not to be regarded as For most applications, the stabilizer will contain apbeing limited to any of the specific. materials or condiproximately 0.15 part to 8 parts by weight of the polytions recited therein except-as set forth in the appended hydric alcohol per part by weight of the phenol. The claims. preferred compositions contain approximately 1 part to Example 1 V 5 B g by welggt the Polyhydnc alcohol Per Part by Resinous compositions containing the stabilizers of this Igh of Q P 6110- e dd d an invention were prepared by milling a base formulation e stablhzer components may e m 1v1 u y and the stabilizer components together for 5. minutesv on to the halogenated polyolefin composition or a mixture a 2 ron differential Speed min at 0 E The stabilized of the comPfments may added' h 31 d composition was then removed from the rolls as a flexible The Stablhzel' EY be Incorporated) the Ogenate homogeneous sheet, 0.025 inch in thickness. The heat polyolefin composition by any convenient procedure. For Stability f the compositions was. detennined by placing example, w halogenatgd polyolefin y, mlxed with 1 x 1 inch specimens which had been cut from the milled lfi alcohol? phencfla a plastlcfzer and sheets in a forced-circulation air oven at 350 F. and mgredlgnts If w1th wlfhout ald of a g removing specimens periodically until degradation was ga gf g 12%;? ii l f ggm ggoug If g complete as indicated by color, change. The specimens 1S Oge were then rated usin the followin color code: bilized resin may then be removed from the mill in the g g form of a sheet or film of the desired thickness which may be used as such or subjected to polishing or em- LY-Llght Yellow bossing treatment. Alternatively, the stabilizer compol nents may be incorporated by dissolving them in a solu- LT-llght tan tion of the resin. This solution may then be used as such, TTan for example, as a varnish for coating or spraying on L BP-Llght'bmwn variousv materials or for casting articles in a mold. Sta- B1'BrWn bilized halogenated polyolefins may also be obtained by Bl-Black removmg h $01v ent from Such a Solution y evaporation The base formulation used in the preparation of the. or steam distillation. v stabilized resinous compositions consisted of 100 parts The stabilized COLHIPOSltIOHS of the present invention by i ht f hl i ted olyethylene (chlorine content, may conta n any or the plasticizers that are ordinarily 56% Parts y Weight of di(ZLIhYIhLXYI)phthalate, employed in halogenated polyolefin compositions. These and 5 parts by weight of epoxidized soybean oil. The stainclude, for example, dioctyl phthalate, dibutyl sebacate, bilizer components and the results of the heat stability and tricresyl phosphate. The plasticizer is generally prestests are shown in Table I.

Y TABLE I 113x! stabilizer components Phr' Golor after Indicated Number of Minutes at 350 F.

' 0 15 so 45 so h 1 LL- f i LY LY Y Y Y LT LT LI T T n arm 1 in".{ggfg ig 4; f 1 lo LY LY LY Y Y Y LT LT LT LT ---igemigimigi-fifiifiiffiijj: i l O LY LY LY LY LY LY Y Y Y t i i figidifilifflijI: i i LY LY LY LY Y Y LT LT LT 1E .{21 fi }o LY Y Y' LT LT LT T T LBr LBr l 1F Z!Z i f }0 Y Y LI T T T LBr LBr Br Br ---{@5512i ailj fiffifflifi jj i Y Y Y Y LT LT T T T T P'l 1H--- {g ag ga ag i LT LT T T LBr LBr Br Br Br Br 1L- j i ifg ii g 1 }L Y Y LT T T T LBr Br Br Br S 01110 7 1 1 Y Y Y LT T T T LBr Br B1 B; {ggigt kggi tifiifitiilBYTE: -1: l LY LY LY Y Y Y LT LT {f tikigfigi figiigfgiflfggit??? i LY LY LY LY Y Y LT LT LT '-t t. h 1M {52%}; i ggggjf fff l ifff fj }LY Y Y Y Y Y Y Y Y Y Y lj sit ipfvierffl'..lllflffiff'ftfiifl 1 l Y LL LL LT LT T L T T L 1o-EEfffff i }o LY LY LY Y Y LT T LBr Br Br {%lmrei i$tit?;jj: .133: i LY LY LY Y Y Y LT T T Br 1Q!" No e Y T '1 B1 B1 B1 1 Part-sv by weight of stabilizer component per 100 parts by weight of chlorinated polyethylene.

2 Technical grade of pentaerythritol marketed by Hayden Newport Chemical Corporation.

Example 2 Example 3 A series of chlorinated polyethylene compositions was prepared in which the stabilizer mixture consisted of a polyhydric alcohol and either 2,2-bis (4-hydroxyphenyl) 5 propane or 2,6-di-tert. butyl-4-methylphenol. The base formulation and the method by which the compositions were prepared were the same as those described in Example 1. The results of the heat stability tests at 350 F. are given in Table HI.

N-salicoyl-p-amin {Pentek Powder- LY Y LT T T L Br B1 Br Bl TABLE II Color after Indicated Number of Minutes at 375 F. 113x. Stabilizer Components Phr.

o so 45 5o 75 so 105 p 120 135 150 rrnggg gg Powder i }0 Y Y LT LT T T LBr Br Br B1 Octylnhpnnl 1 2B Powder 1 }0. LY Y Y LT LT .1 LT. LT. T T T Q g i }o o LY LY LY LY 'Y Y Y Y Y Y 811 e OW 81 2D---{g ;{g fff }0 LY Y Y LT LT LT LBr Br Br B1 2E.- ,$g i }0 LT T T T LBr Br Br Br Br B1 2r gggg 9gggg I i }c LT T T LBr Br Br Br Br Br B1 2am{ggggg lggg i }0 Y LT T T LBr LBr LBr LBr LBr LBr 2H---{ ;f }0 LT T T T LBr LBr Br Br Br B1 {gjj ffgg }LY LT LT T T LBr Br Br Br Br Br {ggggfigggg }LY LT LT T T LBr Br Br Br Br Br --{i ififfi iir i i fl ffffi'fiij'jjj I i LY Y Y LT T T LBr Br Br [2,2-bis (dichloro-4-hydroxyphenyl)propane 1 2L {Pentek Powder 1 }0 LY LY Y LT Tv T LBr Br Br Br 2M {%4'-11tl1 yle1&eb1s(2,6-d1tert.butylphenol) }LY Y Y Y Y Y Y LT LT LT LT en E OW GI 4,4'-thi0biS (6-tert b W1-3 l; 1 {Pentek Powdeh }0 Y LT LT LT T T LBr LBr Br Br p-Chlorothiopheno 21 o LY Y LT LT LT T T Br Br Bl 2Q, Nnne Y T Br B1 TABLE 111 Color after Indicated Number of Minutes at 350 F. 1131:. Stabilizer Components Phr.

0 15 so so 2,2-bis (4-hydroxyphenyl) propane 1 7 3A... {Penpek Powder 1 }c LY LY LY Y Y Y Y Y LT LT 3B"- gggg g i }o LY LY LY Y Y Y Y Y LT LT so---{ifgzf fifiggf }}o LY Y LT T T T LBr LBr LBr LBr 2,2-bis +11 dro hr'ri r'h'fj 1 31) g g fgg Y)? P }o LY Y LT T T T LBr LBr LBr LBr 3E f gjg fi fi f i }o LY LY Y Y Y Y Y Y LT LT rip {2,2-bis (4-hydroxyphenyl) propane 1 3F--- lResmousPolyolx 450 }c LY Y Y LT T T LBr LBr LBr LBr 3G gg f g fgggg i }o LY Y Y LT LT T T T T T (l-L Y- -g11 2,2-bis (4-hydroxyphenyl) propane l 3H---{g ggw g g i a f fiiTi a? %}c Y LT LT T LBr LBr LBr LBr Br Br 1 1'9 uy m en 31----{539 5 ft gggii gfibifia i lo 0 LY LY LY LY LY LY Y Y Y 1-e me riiiii 1ilrl i5fl1rfiaa'- i LY LY LY Y Y Y LT T T T a D1 3K igg?i t gz g ggqx th l he l i }0 LY LY LY Y Y Y LT T T T ,-.uymeypno 3L ggii g st Ei i }0 LY LY Y Y Y LT LT LT T T 1-e uy me yp eno r l rfi ti tfiiii iiiirgisrgaai i }C H LY LY Y Y Y LT T T 3N {fi i }o LY Y LT LT T T LBr LBr LBr LBr 30- N n Y T T Br Br BI 2 Example: 4

A series of chlorinated mlyethylene compositions was prepared in; which the stabili er mixture c nsi ted of. a polyhydrie alcohol; and either; 2 ,2-bis (4-hydroxyphenyl) Example 5 A series of chlorinated polyethylene compositions was prepared in which the stabilizer mixture consisted ofa polyhydric alcohol and a phenol. The; base formulation propane or 2,6.-di-tert., butylA-methylphenol. The base and the method by whichthe compositions were, prepared formulation and the method; by which the compositions were the same as those described in Example 1. The were re ared were the same asthosedescribed. in Exstabilizer com orients, the amounts of eachthat were p p I a v ample 1. The results of the heat stability tests at 3752 are used, and the results oi the heat stabilit 1 tests at, 350 F.

y given in Table IV. are given in Table V.

TABLE IV Color afterlndieated Number of Minutes at'375" F.

Ex. 2 zer omponen s st bili G t Phr 7 No.

{2,2bis (4-hydroxyphenyl) propane 1 4A [Fem]; Powder 1 LY Y Y LT LT T a T LBr Br Br r1; "g! Pmpane i }c LY Y LT LT T T T LBr Br Br 2,2-bis. (4-hydroxyphenyl) propane N 1 l 40--- {5 3 g} gycolflhwii 1 o Y LT LT T T LBr Br Br B1 is y roxyp eny propane -"lTrigetglyllolgthaneilnflii i Y LT T T LEI Br B1 n 22 is 4- y roxyp eny propane "i {Tgipengirilryghritolifnij g LY Y LT LT T T T L Br B1" Br 2, -bis y roxyp eny propane V 4F--- ig g k ig g o LY LT LT T T Lara Br .Br Bl ,2- is y oxyp eny propane. lafifthzlfilglucosigemij T LY Y LT T T T LBI B1 2, is 4 y oxyp eny propane. 4H g z fi gi i i giTi }0 LT T T T L Br LBr LBr Br- B1'- B1 2,6-'-e. uy me ypeno. v 41---- g g fi g gii fi l fi }c o LY LY LY LY Y Y Y Y Y 2,6- -e uy me yp e r 41-". {g gg t g g t 1 1 1 h A 1 E0 LY LY Y Y LT T T LBr Br Br ,6-'-e. uy me ypeno. i I 4K.{gg d% g fi? iHTH c LY LY Y Y LT T T LBr Br Br -e. uy me ypeno. I 4L.-. gx t g t l 35 811 1 h }o LY Y Y LT LT T T LBr L r LBr 2, "-ter uy -me yp eno- I 4M gi ag ggg th 1 h 1 }c LY LY Y Y LT T T LBr LBr LBr 2, 1-tert. uty me y p eno I 4N-.. {Hydroxyethylcenulqse l }0 Y Y LT T T T LBr Br Br Br 40 one V Y T B1 B1 TABLE V Stabilizer Components Color After Indicated Number of Minutes at 350 F. Ex. No.

Phenol Phr. Polyhydric Alcohol Phr. 0 15 30 45 60 75 so 105 5A 2, 2 bi s (4-liydroxy- 1 Pentek Powder 1 C LY LY LY Y Y Y Y Y LT LT phenyl) propane.

d 2 2 0 LY LY Y Y Y Y Y LT LT LT 3 3 0 LY LY Y Y Y Y LT LT LT LT 5 1 c Y LT LT T T T L Br L Br L Br L Br 1 5 c LY LY LY Y Y Y Y Y Y Y 1 1 c C LY LY LY LY LY LY Y Y Y 2 2 C C LY LY LY LY LY Y Y Y T 5 1 C LY Y Y LI LT T T L Br L Br L Bl 7 do 1 5 0 C LY LY LY LY LY LY LY Y Y 5.1--.. 2,2-bis (Lhy 2 2 C LY Y Y Y LT LT LT 'T T T phenyl) propane. 5K0" (lo 5 l C Y LT LT LT T T T L.Br Br Br 1 5 C LY Y Y Y LT LT LT T V L B: L Br 2 2 c LY Y Y Y LT LT LT T T T 5 1 0 Y LT LT LT T T T vL Br L Br L Br 1 5 c Y Y Y Y LT 7 LT LT T L Br L Br 2 2 c LY LY Y Y LT LT T T L Br L Br 5 1 0 Y LT LT LT T T T L Br L Br L Br 1 5 C Y Y Y Y LT LT LT T L B1- L Br 2 2 C LY Y T T L Br. L Br L Br Br B1 131' 5 1 c Y LT LT LT LT T T T Br Br 1 5 0 Y Y Y Y Y LT 1 LT T L Br L Br 2 2 -0 0 LY LY LY LY LY LY Y Y Y phenol.

d 5 1 c LY Y Y LT LT LT T T T T V 1 5 C 0' LY LY LY LY LY LY LY Y Y atoms, nitro, carboxyl, and hydroxyl and n represents a number in the range of zero to 3 and phenols having the For comparative purposes, a series of chlorinated polystructure ethylene compositions was prepared in which the stabilizer was either a polyhydric alcohol or a phenol. The base 5 E0 OH formulanon and the method by which the compositions were prepared were the same as those described in Exam- B ple 1. The results of the heat stability tests at 350 F. are given in Table VI. u u

TABLE VI Color after Indicated Number of Minutes at 350 F. 113x. Stabilizer Phr.

A.- Pentek Powder 1 O LY LY Y Y LT T T LBr Br B1 n do 3 o 0 LY LY Y Y LT T L Br Br Br 5 o o LY LY LY Y LT T L Br Br Br 1 c o LY LY Y Y LT T L Br Br Br 3 0 o LY LY Y Y LT T L Br Br Br ]3 dn 5 o o LY LY LY Y LT T L Br Br Br G Trimethylolethane 1 C LY Y Y Y LT T L Br Br Br H do 3 0 LY LY Y Y Y LT T L Br Br Br I do a o LY LY LY Y Y LT T L Br Br Br J' Neopentyl glycoL 1 C LY Y Y LT T T T LBr Br Br K do 3 o LY Y Y Y LT T T T L Br Br L dn 5 C LY Y Y Y LT T T T L Br Br M Besinous Po1 o1X-450 3 C Y Y LT LT LT T L Br L Br Br Br N do 5 0 Y Y LT LT LT T L Br L Br Br Br O 2,2-bis (A-hydroxyphenyl) propane 1 Y Y Y LT LT LT T T T L Br Br 2,6-di-tert. butyl+methylphenol 1 LY LY Y Y LT LT LT T '1 L Br L Br The foregoing examples have illustrated the manner in 30 wherein each R represents a member selected from the which the novel stabilizers may be combined with a halogenated polyolefin to form compositions that may be used in the preparation of calendered sheets and films. In addition these stabilizers may be used with chlorinated polyethylene or other halogenated polyolefins in plastisol, organosol, extrusion, injection molding, and solvent formulations to form products that are characterized by good color and clarity and excellent heat stability.

What is claimed is:

1. A thermally stabilized resinous composition comprising chlorinated polyethylene containing approximately 20% to 70% by Weight of chlorine and approximately 2% to 6% based on the weight of said chlorinated polyethylene of a stabilizer, said stabilizer comprising a polyhydric alcohol selected from the group consisting of pentaerythritol and sorbitol and a phenol selected from the group consisting of phenols having the structure wherein X represents a substituent selected from the group consisting of halogen, alkyl having from 1 to 8 carbon group consisting of hydrogen and lower alkyl, R" represents a member selected from the group consisting of lower alkyl and halogen, and n represents a number in the range of zero to 3 and containing approximately 0.15 part to 8 parts by Weight of said polyhydric alcohol per part by Weight of said phenol.

2. The composition of claim 1 wherein the polyhydric alcohol is pentaerythritol.

3. The composition of claim 1 wherein the polyhydric alcohol is sorbitol.

References Cited UNITED STATES PATENTS 2,183,556 12/1939 Fawcett et a1 26094.9 2,480,009 8/1949 Fletcher 26040.85 2,578,904 12/ 1951 Stamatofi 260-45 .95

FOREIGN PATENTS 702,848 5/1951 Great Britain. 797,054 6/1958 Great Britain.

DONALD E. CZAJA, Primary Examiner. LEON J. BERCOVITZ, Examiner. H. E. TAYLOR, JR., Assistant Examiner. 

1. A THERMALLY STABILIZED RESINOUS COMPOSITION COMPRISING CHLORINATED POLYETHYLENE CONTAINING APPROXIMATELY 20% TO 70% BY WEIGHT OF CHLORINE AND APPROXIMATELY 2% TO 6% BASED ON THE WEIGHT OF SAID CHLORINATED POLYETHYLENE OF A STABILIZER, SAID STABILIZER COMPRISING A POLYHYDRIC ALCOHOL SELECTED FROM THE GROUP CONSISTING OF PENTAERYTHRITOL AND SORBITOL AND A PHENOL SELECTED FROM THE GROUP CONSISTING OF PHENOLS HAVING THE STRUCTURE 